This invention relates generally to the field of surgical knives and, more particularly, to ophthalmic surgical knives.
A variety of surgical knives may be used during ophthalmic surgery to make or modify the opening incision into the globe. These knives are generally made from stainless steel or diamond. While steel knives can be used more than once, most steel knives are intended to be a single use disposable product. Diamond knives are designed to be a reusable item because diamond knives are expensive relative to steel knives.
There has been increasing interest in developing a reusable or limited reusable steel knife. One of the problems of developing such a knife is the damage that the unprotected knife blade might receive when being resterilizing between uses. Various knife guards are available, but have proven to be unsatisfactory.
For example, U.S. Pat. No. 5,254,128 discloses a knife with an extendable sleeve that may be alternatively moved to protect the blade or retracted to expose the blade for use. The locking mechanism for this sleeve is disclosed as being either a screw thread or a spring-loaded ball that locks within a groove. This patent also mentions the use of a bowed leaf spring attached at both ends with a projection that snaps into a groove. The screw thread embodiment of this invention requires the use of two hands to operate and restricts cleaning and sterilization procedures. The spring-loaded ball is expensive and complicate to manufacture, and the bowed spring does not allow for independent adjustment of opening and closing force.
Accordingly, a need continues to exist for a surgical knife having a retractable blade guard that is simple and inexpensive to manufacture and that can be operated with only one hand.
The present invention improves upon the prior art by providing a knife having a handle into which a knife blade may be inserted. The blade end of the handle is of reduced diameter and contains a pair of spring-like cantilevered locking arms. The locking arms terminate in a clasping mechanism that interact with a latch contained within a bore in a sheath. The bore is sized and shaped to reciprocate linearly over the blade end of the handle so as to alternatively cover the blade for storage or expose the blade for use.
Accordingly, one objective of the present invention is to provide a knife having a handle with a pair of spring-like cantilevered locking arms.
Another objective of the present invention is to provide a knife having a reciprocating sheath that alternatively covers the blade for storage or exposes the blade for use.
These and other advantages and objectives of the present invention will become apparent from the detailed description and claims that follow.